Derivatives of diphenylamine

ABSTRACT

Derivatives of diphenylamine or phenylnapthyl-amine of the types   WHERE R1, R9 and R12 are phenyl or p-tolyl groups and the remaining R&#39;&#39;s, X and Y may be alkyl or various other substituents, are useful antioxidants for lubricating oils or for various polymeric substrates (e.g., polypropylene) especially in combination with a dialkyl thiodipropionate. A typical antioxidant is 4,4&#39;&#39;-bis-(alpha,alpha,ptrimethylbenzyl)diphenylamine made by reacting p,alphadimethylstyrene with diphenylamine.

United States Patent [1 1 Wheeler Sept. 11, 1973 DERIVATIVES OFDIPHENYLAMINE Edward L. Wheeler, Woodbury, Conn.

[73] Assignee: Uniroyal, Inc., New York, N.Y.

[22] Filed: July 16, 1971 [21] Appl. No.: 163,443

Related US. Application Data [62] Division of Ser. No. 787,577, Dec. 27,1968, Pat. No. 3,649,690, which is a division of Ser. No. 540,817, April7, 1966, Pat. No. 3,505,225.

[75] Inventor:

[52] US. Cl. 260/390, 260/518 R, 260/570 R [51] Int. Cl. C091) 11/12[58] Field of Search 260/390, 570 R [56] Reterences Cited UNITED STATESPATENTS 3,425,985 2/1969 Freytag et a1. 260/570 R PrimaryExaminer-Lorraine A. Weinberger Assistant Examiner--L. Arnold ThaxtonAttorney-James J. Long [57] ABSTRACT Derivatives of diphenylamine orphenylnapthyl-amine of the types iQ-EQ 3 Claims, No Drawings 1DERIVATIVES OF DIPHENYLAMINE This application is a division of mycopending application Ser. No. 787,577, filed Dec. 27, 1968, now U.S.

2 zinc, cadmium, nickel, lead, tin, magnesium, or copper, Y is ahydrogen, methyl, ethyl, sec-alky] containing from three to ten carbonatoms, chlorine, or bro- Pat. 3,649,690, issued Mar. 14, 1972, which isin turn 5 mine radical;

a division of my application Ser. No. 540,817, filed Apr. 7, 1966, nowU.S. Pat. No. 3,505,225, issued Apr. 111 x 7, 1970. R

la H

mines and their use either alone, in combination with Y each other, orin combination with dialkyl 3,3'-thiodipropionates, for the protectionof organic materials where R, is a phenyl or p-tolyl radical,

vated temperatures. Examples of materials which are Containing from onet0 carbon atoms, subject to oxidative deterioration at elevated temperayradical containing from one to ten carbon tures either in the course oftheir processing or fulfilling amms which y he g chain branched,

mers, polyamides, polyesters, polyacetals, acrylonitrilebmmine radicals;butadiene-styrene thermoplastics, and lubricants of the petroleum oiltype or of the synthetic type. r v

This invention relates to new antioxidants which are derivatives ofdiphenylamine and the phenylnaphthyla- 10 having relatively low olefinicunsaturation, which are R and l1, at methyl, phenyl or p-tolyl radicals,subject to oxidative deterioration, particularly at ele- R515 aliy g mpy. secondary, or tertiary ky their prescribed function and which areprotected by X Y are hydrogen, methyl, i yl the compounds f theinvention are h fi poly- 29 taming from three to ten carbon atoms,chlorine or RI The compounds of the invention are represented by G5 N lothe following formulae: ll

where R is a phenyl or p-tolyl radical R and R are methyl, phenyl orp-tolyl radicals, R is a p-tolyl or neopentyl radical, R, is a methyl,phenyl, p-tolyl or 2-phenylisobutyl radical, v R, is a methyl radical;-

where R R,, R, and R, are as defined in formula I, R, is a methyl,phenyl, p-tolyl or neopentyl radical, R is a methyl, phenyl, or p-tolylradical,

X is a methyl, ethyl, sec-alkyl containing from three to ten carbonatoms, alpha, alpha-dimethylbenzyl, alpha-methylbenzyl, chlorine,bromine, carboxyl or metal carboxylate radical where the metal is whereR, is a phenyl or p-tolyl radical,

R is a methyl, phenyl, p-tolyl or 2-phenylisobutyl radical,

R is a methyl, phenyl or p-tolyl radical; or

TYPE I R1 R4 l N a Rs I Br 2 2 4 B5 Be (a) phenyl phenyl phenylneopenty1....- methyl methyl. (b) p-tolyl methyl 7. methyl p-tolyl doDo.

TYPE II X 1'11 l R2C- N-CRs l H l R; R

R1 R2 R3 R4 R5 R1 X Y (1) phenyL. methyl.. methyl. phenyl metllyL...methyl Alpha,alpha-dimethylbenzyl. hydrogen. Bromo bromo.

carboxyl hydrogen nickel carboxylate Do. yl Do. -ootyl Do. -hexyl Do.

R1 R2 R3 R3 X Y methyl; isopropoxy hydrogen hydrogen. do hydrogen2-octyl... Do. phenyl ..do.. 2-hexyl D0.

TYPE IV R9 H (L N .-R|o

ltn

R015 phenyl and Rm and Ru are methyl.

TYPE V 1'! R12 10 ll.

1: 1: Rn u (1 hen l moth l meth l Hydrogen. (2i "Rani "def "defAlplia,ulpha-dliiiothylbe zyl.

In a preferredsfib class of' chemicals of formula II, the substituentshave the following values:

R and R are phenyl or p-tolyl,

R R R and R are methyl,

X is methyl, ethyl, sec-alkyl containing from three to ten carbon atoms,alpha, alpha-dimethylbenzyl, alpha-methylbenzyl, carboxyl or metalcarboxylate where the metal is zinc, cadmium, nickel, lead, tin,magnesium, or copper, and

Y is a hydrogen, methyl, ethyl, or sec-alkyl containing from three toten carbon atoms.

It has previously been known to employ 4,4- bis( 1,1,3,3-tetramethylbutyl)diphenylamine as an antioxidant for rubber.

U.S. Pat. No. 2,943,112 to Ivan C. Popoff et al. describes the use ofalpha-methylstyrene to reduce the amount of unreacted diphenylamine ormonoalkylated diphenylamine present after alkylating the diphenylaminewith a C5' C olefin.

U.S. Pat. No. 2,543,329 to C. S. Myers describes the stabilization ofpolyethylene with diphenylamine.

U.S. Pat. No. 2,519,755 to M. F. Gribbins describes the use of a dialkyl3,3'-thiodipropionate as a stabilizer for polyethylene.

U.S. Pat. No. 3,072,603 to E. C. Tholstrup describes the stabilizationof poly-alpha-olefins by use of a stabilizer combination consisting of adiester of 3,3'-thiodipropionic acid and a nitrogen-containing compoundof the following types:

(1964) and also disclosed as a rubber antioxidant by A. W. Campbell U.S.Pat. 1,902,115 (Mar. 21, 1933) and U.S. Pat. 1,950,079 (Mar. 6, 1934)although the described structure was incorrect.

As indicated previously the present derivatives of diphenylamine andphenylnaphthylamines are effective antioxidants for materials of lowunsaturation. The materials of low unsaturation include essentiallysaturated polymers, whether resins or rubbers, such as the alphaolefinpolymers including resinous homopolymers of alph-olefins (e.g.,polyethylene, polypropylene) or the rubbery copolymers of two or moredifferent alphaolefins (e.g., ethylene-propylene rubber, known as EPM).Also included are resinous or rubbery polymers having a minor amount ofunsaturation, such as the alpha-olefin polymers which are rubberyterpolymers of two or more different alpha-olefins with at least onenon-conjugated diolefin (e.g., rubbery terpolymers of ethylene,propylene, and di-cyclopentadiene, 1,4- hexadiene, methylene norbornene,cyclo-octadiene, or the like, known as EPDM these ordinarily containless than of olefmic unsaturation (i.e., less than 25% by weight of thediolefin). Similarly, the acrylonitrile- 'but adiene-styrenepolymers(called ABS' thermoplastics) may be employed. These are usually either(1) graft copolymers of styrene and acrylonitrile on a poly- -butadienerubber spine or on a butadiene-styrene rub- 'ber spine (with or withoutadditional separately prepared styrene-acrylonitrile resin), or (2)physical mixtures of styrene-acrylonitrile resin withbutadieneacrylonitrile rubber. The olefinic unsaturation (i.e.,butadiene content) of such ABS compositions is frequently less thanOther polymers useful in the invention include the polyamides (nylon),polyesters (e.g., polyethylene terephthalate or copolymers thereof,notably in the form of fibers or films), acetal resins (polymers orcopolymers as described for example in Modern Plastics Encyclopedia,1966, pages 109-113; see also U.S. Pat. 3,027,352). The presentchemicals are useful also as antioxidants for lubricants, whetheressentially natural lubricating oil obtained from petroleum, orsynthetic lubricants of the type represented by such ester lubricants asalkyl esters of dicarboxylic acids (for example those in which the alkylgroup has six-l8 carbon atoms and the dicarboxylic acid has six-l8carbon atoms) or fatty acid (e.g., C,,-C acids) esters of polyols suchas neopentyl glycol, trimethylol propane, pentaerylthritol, or the like(see Synthetic Lubricants by Gunderson et al., Reinhold, 1962).

The present antioxidants are effective in the conventional amountsordinarily used for protecting substrates from oxidation, usually withinthe range of from 0.0l% to 4% by weight, based on the weight of thesubstrate.

The presently employed derivative of diphenylamine and thephenylnaphthylamines are more effective than the parent compound or theknown 4,4'-dialkyldiphenylamines either alone, in combinations, or incombination with dialkyl 3,3'-thiodipropionates (in which the alkylgroups typically contain from eight to 20 carbon atoms). The relativeproportions of the present chemicals and the dialkyl3,3'-thiodipropionate are not critical and may be in accordance withconventional practice, usually from 0.01% to 4% of the antioxidantchemical and from 4% to 0.01% of the dialkyl 3,3-thiodipropionate. I

The derivatives of the phenylnaphthylamines are discoloring but areeffective high temperature antioxidants, and in synthetic lubricants ofthe ester type produce less sludge than the parent compounds.

The diphenylamine derivatives are less discoloring than those of priorart and surprisingly in the presence of dialkyl 3,3'-thiodipropionatesto show no discoloration after thermal aging.

The compounds of the invention such as shown in Formula I may beprepared by alkylating the appropriate diphenylamine orphenylnaphthylamine with the appropriate olefin using a suitable acidcatalyst such as alu-minum chloride, zinc chloride, or acid clay. Wherethere are two groups of different structure on the diphenylamine nucleusa stepwise alkylation may be carried out. In the compounds whichcontained a trityl group, triphenyl-methyl cloride may be used as thealkylating agent.

The unsymmetrical diphenylamines may be prepared in two ways.

a. by condensing an appropriately substituted aniline witho-chlorobenzoic acid. The carboxyl broup may be removed, when desired,by thermal decarboxylation. The final unsymmetrical product may beobtained by reacting with the appropriate alkylating agent using an acidcatalyst.

b. by alkylating diphenylamine with a vinyl type olefin (i.e., butene-l,octene-l) and separating the predominant Z-aIkyl-diphenylamine or2,2'-dialkyldiphenylamine. This product may then be reacted with theappropriate alkylating agent using a typical acid catalyst to obtain thefinal product.

Since vinyl type olefins such as butene-l-alkylate preferentially in theortho position of diphenylamine and vinylidene type olefins such asalpha-methyl styrene and 2,4,4-trimethylpentene-l alkylatepreferentially in the para position of diphenylamine, some of thedescribed compounds can be prepared in one step by alkylating with themixtures of olefins, or by sequential alkylation using first one olefinthen the other, without isolation of the intermediate.

Although the alkylation reactions occur primarily as described, in anypreparation mixtures of ortho and para isomers as well as mono, di andtri alkylated products occur. Furthermore in alkylations such as thereaction of diphenylamine with octene-l some isomerization of the olefinoccurs giving some 2-(alpha-ethylhexyl)diphenylamine as well aspredominant 2-(alphamethylheptyl)diphenylamine. Since these isomers aredifficult to separate, it is a preferred embodiment of the invention touse the reaction mixtures containing primary product and small amountsof the isomeric materials in preparing the antioxidants of theinvention. Example I The preparation of 4-( l ,l ,3,3-tetramethylbutyl)-4triphenylmethyldiphenylamine.

A mixture of 169 g. of diphenylamine and 30 g. of anhydrous aluminumchloride was heated to C. with stirring. 112 g. of diisobutylene wasadded dropwise over a one hour period. An exotherm occurred and thetemperature was maintained at l 15C. during the addition. The mixturewas heated at l25l 35C. for an additional hour, then cooled and pouredinto water. 400ml. of benzene was added and the organic layer wasseparated, washed and dried. The benzene was removed by distillation andthe residue product was fractionally distilled under reduced pressure.The fraction boiling at 160l75C. (0.5mm) was the 4-(1,l,3,3-tetramethylbutyl)di-phenylamine.

A. mixture of 28.1 g. of 4-(l,l,3,3-tetramethylbutyl)diphenylamine, 27.9of triphenylmethyl chloride, 500 ml. of acetic acid and 50 ml. ofconcentrated hydrochloric acid was heated under reflux. 25 ml. of aceticacid-water mixture was removed by distillation during the first hour,then the mixture was refluxed an additional 2% hours. The reactionmixture was poured into water and the resulting solid was removed byfiltration. The solid was slurried with benzene and heated under reflux,then filtered hot to remove any insoluble material. The filtrate wasevaporated to dryness and the crude product (27 g.) recrystallized threetimes from hexane m.p. 203-205C. Analysis Calculated for C HuN:

Found:

N, 2.85 E a p e l The preparation of 4,4'-bis(alpha, alpha, p-trimethylbenzyl)diphenylamine.

'A mixture of 169g. of diphenylamine, 25 g. ofMontp,alpha-dimethylstyrene was added over a one-hour pe- 1 riod and thereaction was maintained at 135C. for four hours. The catalyst wasremoved by filtration and the product was crystallized from hexane, m.p.102-103C.

Analysis Calculated for C H Nz Found:

N, 3.21 Example 111 The preparation of2,4,4'-tris(alpha-dimethyl-benzyl)diphenylamine.

A mixture of 85 g. of diphenylamine, 13.3 g. of anhydrous aluminumchloride, and 200 ml. of n-hexane was heated at the reflux temperaturewith stirring. 206 g. of alpha-methyl styrene was added dropwise during1% hours, and the mixture was stirred at 80-85C. for 4% hours. Thereaction mixture was cooled and poured into water, the organic layerseparated and washed three times with water, and the solvent was removedby distillation. The product was vacuum topped to 200C (0.5 mm.).Crystallization of the crude product (216 g.) from hexane removed mostof the more insoluble4,4'-bis-(alpha,a1pha-dimethylbenzyl)diphenylamine. The filtrate wasevaporated to dryness and the residue product (145 g.) recrystallizedtwice from isopropanol to obtain 49g., m.p. 1l4116C. An analyticalsample was prepared by chromatographing g. of the compound on 250 g. ofalumina using 20% benzene-80% hexane as the eluent. The first fractionsobtained were evaporated and recrystallized twice from hexane, m.p.121.5122.5C.

Analysis Calculated for C l-l Nz M01 Wt. 523.

Found: C, 89.5;11, 7.86 N, 2.63

M01 Wt. 531.

Example IV The preparation of 2,2-dibromo-4,4'-bis(alpha,alpha-dimethylbenzyl)diphenylamine.

To a stirred solution of 40 g. of4,4'-bis(alpha,alphadimethylbenzyl)diphenylamine in 300 ml. of glacialacetic acid was added 32 g. of bromine dissolved in ml. of glacialacetic acid at room temperature. After the addition was complete themixture was heated at 45C for 10 minutes and the product was removed byfiltration. The crude dibromo derivative was dissolved in benzene andthe solution extracted with dilute sodium hydroxide, then washed withwater. The benzene was evaporated and the product was recrystallizedfrom isopropanol to obtain 39 g., m.p. l66167C.

Analysis Calculated for C H B N;

C, 63.9; H, 5.15; N, 2.49 Br, 28.4 Found: C, 63.5; H, 5.20; N, 2.77; Br,28.1.

Example V The preparation of4,4-bis(alpha,alpha-dimethylbenzyl)-2-carboxydiphenylamine.

187 g. of N-phenylanthranilic acid, prepared according to Org. Syn.Coll. Vol. ll p. 15, was dissolved in 500 ml. of a solution containing50 g. of potassium hydroxide. The insoluble material was removed byfiltration. To the aqueous solution was added an aqueous solutioncontaining 71 g. of zinc sulfate. The zinc N- phenylanthranilate wasseparated by filtration and dried.

A mixture of 1 10 g. of zinc N-phenylanthranilate, 30 g. of zincchloride and 500 ml. of 1,2-dichloroethane was heated under reflux withstirring. 1 18 g. of alphamethyl styrene was added dropwise over atwenty minute period and the mixture heated under reflux for six hours.The reaction mixture was poured into water and chloroform added. Theorganic layer was separated and washed with dilute hydrochloric acid,then with water. The solvent was removed by distillation and the productrecrystallized from isopropanol to obtain 88 g. of product, m.p.197-199C. Further recrystallization gave material which melted 198199C.

Analysis Calculated for C l-1 N0 2 C, 82.9; H, 6.90; N, 3.12.

Found: C, 82.0; H, 7.22; N, 3.32

Example Vl The preparation of nickel 4,4'-bis(alpha,alphadimethylbenzyl)diphenylamine-2-carboxylate.

4.5 g. of 4,4'-bis(alpha, alpha-dimethylbenzyl)-2-carboxydiphenylaminewas dissolved in 100 ml. of 0.01N sodium hydroxide. 30 ml. of ethanolwas added to aid solution and the solution was filtered to remove anyundissolved material. 1.44 g. of nickel sulfate dissolved in 50 ml. ofwater was added to this solution with stirring and the resultingprecipitated nickel salt was filtered and dried at 50C.

Example VII The preparation of2-sec-butyl-4,4'-bis(alpha,alphadimethylbenzyl)-diphenylamine.

A mixture of 169 g. of diphenylamine, 73 g. of butene-l and 25 g. ofMontmorillonite clay (Girdler Catalysts' designation KSF/O) was heatedfor 5 hours at C. in one liter stirred autoclave. The catalyst wasremoved by filtration and the residue combined with a second reactionmixture obtained under similar reaction conditions. The crude mixturewas purified by fractional distillation under reduced'pressure. Thefraction boiling at 136-137C. (1.4 mm) was 2-secbutyldiphenylamine.

A mixture of 66 g. of 2-sec-butyldiphenylamine, 10 g. of Montmorilloniteclay (Girder Catalysts KSF/O), and 30 ml. of toluene was heated withstirring to 130+C. 76.5 g. of alpha-methylstyrene was added over aone-half hour period and the reaction temperature was maintained at130-135C. for 5 hours. The catalyst was removed by filtration, and thesolvent was removed by distillation. The viscous residue product wasfractionally distilled under reduced pressure. The fraction boiling at240C. (0.25 mm) was the 2-sec-butyl- 4,4'-bis(alpha,alpha-di-methylbenzyl) diphenylamine. Analysis Calculated for C H N:

C, 88.5; H, 8.46; N, 3.04.

Found: C, 88.6; H, 8.28; N, 2.87.. Example V111 The preparation of4,4'-bis(alpha,alphadimethylbenzyl)-2-(alpha-methylheptyl)diphenylamine.

A mixture of 592 g. of diphenylamine, 471 g. of octene-l and 59 g. ofMontmorillonite clay (Girdler Catalysts designation KSF/O), previouslydried at 120C. for 3 hours, was heated at 175C. for 6 hours in a 2-literMagne-Dash autoclave. The catalyst was removed by filtration and thecrude product subjected to fractional distillation. The fraction boilingat 150l70C (0.2 mm) weighed 395 g. and assayed 85% 2-(alphamethylheptyl)diphenylamine.

A mixture of 56 g. of 2-(alpha-methylheptyl)diphenylamine, 8.5 g. ofMontmorillonite clay (Girdler Cat-alysts designation KSF/O), previouslydried at 120C for 16 hours, and 50 ml. of toluene was heated to 130Cwith stirring. 52 g. of alpha-methylstyrene was added during a twentyminute period and the stirred mixture was maintained at 130C. for 4hours. The catalyst was removed by filtration and the crude product wasfractionally distilled under reduced pressure. The fraction distillingat 280C. (0.5 mm) was the desired product.

Analysis Calculated for C i-I N:

C, 88.2; H, 9.09; N, 2.71.

Found: C, 88.2; H, 9.05; N, 3.00. Example [X The preparation of2-(alpha-methylpentyl)-4,4'- ditrityldiphenylamine.

A mixture of 25.3 g. of 2-(alpha-methylpentyl)- diphenylamine, 58.5 g.of trityl chloride, 2.5 g. of alu minum chloride and 50 ml. of benzenewas heated under re-flux for 3% hours. 10 ml. of ethyl ether was addedafter cooling and the mixture was-then poured into water. The aqueouslayer was removed and the organic layer was poured into an equal volumeof hexane. The resulting precipitate 78 g. was filtered. A pure samplewas obtained by chromatography on alumina using benzene as the eluentfollowed by recrystallization from a 1:1 benzene-isopropanol mixture.The sample was dried under vacuum at 78C for 8 hours, mp. 220.-

Analysis Calculated for C, 91.2; H, 6.92, N, 1.90.

Found: C, 91.3; H, 7.38; N, 1.73.

Example X The preparation of 4(alpha,alpha-dimethylbenzyl)-4'-isopropoxydiphenylamine.

A mixture of 56.8 g. of isopropoxydiphenylamine, 5 g. of anhydrousaluminum chloride and ml. of nhexane was heated at the refluxtemperature with stirring. 30.7 g. of alpha-methylstyrene was addeddropwise and after the addition was completed the mixture was heated anadditional four hours at 7075C. The reaction mixture was pured intowater and benzene was added to facilitate separation. The benzene layerwas washed with dilute sodium hydroxide, then water, and dried oversodium sulfate. The benzene was removed by distillation and the crudeproduct was fractionally distilled. 51 g. of product was obtained: b.p.211-216C. (0.3 mm).

Analysis Calculated for C, 83.4; H, 7.88; N, 4.05.

Found: C, 8.31; H, 8.35; N, 4.08.

Example XI The preparation of 2-(alpha-methylheptyl)-4'-(alpha,alpha-dimethylbenzyl)diphenylamine.

A mixture of 39.5 g. of 2-(alpha-methylheptyl)- diphenylamine and 6 g.of Montmorillonite clay (Girdler Catalysts designation KSF/O) was heatedto C. and 20 g. of alpha-methylstyrene was added over a 10 minuteperiod. The mixture was heated at 120130C. for four hours. The reactionmixture was diluted with benzene and the catalyst was removed byfiltration. The solvent was removed by distillation and the residueproduct was purified by fractional distillation under reduced pressure.The fraction boiling at 200C (04 mm) was the desired product. AnalysisCalculated for C, 87.2; H, 9.27; N, 3.51.

Found: C, 87.1; H, 9.22; N, 3.82. Example XII The preparation of2-(alpha-methylpentyl)-4'- trityldiphenylamine.

A mixture of 846 g. of diphenylamine, 547 g. of hexene-l and 85 g. ofMontmorillonite clay Girdler Catalysts designation KSF/O) was heated ina one gallon stirred autoclave for 6 hours at 225C. The reaction mixturewas diluted with toluene and the catalyst removed by filtration. Thesolvent and excess hexene-l were removed by distillation and the crudeproduct was purified by fractional distillation through a 10 inch columnpacked with Berl saddles. The fraction boiling at 117-121C. (0.1 mm) was2-(alpha-methylpentyl)- diphenylamine.

A mixture of 50.6 g. of 2-(alpha-methylpentyl)- diphenylamine, 27.9 g.of trityl chloride, 5 g. of anhydrous aluminum chloride and ml. ofbenzene was heated at the reflux temperature for 3 hours. The reactionmixture was pured into water and the organic layer separated and washedfour times with water. The solvent was removed by distillation and theunreacted staring material removed by distillation under reducedpressure, b.p. 123C. (0.3 mm). The residue product was chromatographedon alumina using 20% benzene- 80% hexane as the eluent. The product thusobtained was recrystallized twice from hexane to obtain the desiredproduct: m.p. 6771C.

Analysis Calculated for C, 89.7; H, 7.48; N, 2.83.

Found: C, 89.8, H, 7.40; N, 3.07.

1 1 Example XIII The preparation ofN-(4-alpha,alpha-dimethylbenzylphenyl l -naphthylamine.

A mixture of2l9 g. of N-phenyl-l-naphthylamine, g. of Montmorilloniteclay (Girdler Catalysts designation KSF/O) and 300 ml. of toluene washeated to the reflux temperature and 100 ml. of toluene was distilledfrom the mixture. The reaction mixture was maintained at lC. and 260 g.of aIpha-methylstyrene was added dropwise over a 1 hour period. Themixture was heated an additional 4 hours at 135C. The catalyst wasremoved by filtration and the product vacuum topped to 200C. (1.0 mm).The crude product was purified by chromatography on alumina usingbenzene-hexane mixtures as the eluent, followed by tworecrystallizations from hexane. The pure product after drying undervacuum at 78C. for 6 hours melted at 9I.592.5C.

Analysis Calculated for C ,,H N:

C, 89.0; H, 6.87, N, 4.15.

Found C, 89.0; H, 7.06; N, 4.04.

Example XIV The preparation ofN-(4-alpha,alpha-dimethylbenzylphenyl)-1-(alpha,alpha-dimethylbenzyl)-2-naphtyl-amine.

A mixture of2 l9 g. of N-phenyl-2-naphthylamine, 30 g. of anhydrousaluminum chlorida, and 250 ml. of benzene was heated with stirring to70-75C. 260 g. of alpha-methylstyrene was added dropwise during a onehour period and the reaction mixture was maintained at 70-85C. for fourhours. The mixture was poured into water, more benzene was added and thebenzene solution was washed twice with water. The benzene was removed bydistillation and the crude product vacuum topped at 200C. (0.4 mm). 394g. of residue product was obtained. A pure product (m.p. I2l.5l22.0C.)was obtained by two recrystallizations from a benzenehexane mixture.

Analysis Calculated for C I-I N:

C, 89.6; H, 7.30; N, 3.08;

M01 Wt. 456. Found: C, 89.8; H, 7.49; N, 3.12; M01 Wt. 471. Example XVThe preparation ofN-(4-alpha,alpha-dimethylbenzylphenyl)-2-naphthylamine.

A mixture of 110 g. of N-phenyl-Z-naphthylamine, 12.5 g. ofMontmorillonite clay (Girdler Catalysts designation KSF/O) and 150 ml.of toluene was heated at the reflux temperature with stirring. Water wasremoved from the catalyst by azeotropic distillation along with 100ml.of toluene. 65 g. of alpha-methylstyrene was added dropwise over aone-half hour period and the reaction mixture was maintained at 100C.for two hours. The catalyst was removed by filtration and the solventremoved by distillation. The product was crystallized from hexane andafter two recrystallizations from hexane melted at 92.0-92.5C.

Analysis Calculated for C ,,H N:

C, 89.0; H, 6.87; N, 4.15.

Found: C, 88.6; H, 7.07; N, 3.85 Example XVI In this example thecompounds of the invention were tested as stabilizers for polyacetalresins against thermal degradation.

The solid stabilizers were incorporated into unstabilized acetalcopolymer resin based on trioxane (Celcon CKX-205," see Modern PlasticsEncyclopedia, 199, page lll, or US. Pat. No. 3,027,352), by dry blendingfor 5 minutes using a Waring Blender. Liquid stabilizers wereincorporated by dissolving in a suitable solvent, slurrying with theresin and steaming under vacuum to remove the solvent. Five grams of thepowdered resin containing 0.5% by weight of the stabilizer was placed inan open aluminum cup and exposed in a 230C. oven for 45 minutes, and theloss in weight of the polymer was determined.

TA B LE I Compound Weight Loss Control 3 I .9 4-( LI,3,S-tetramethylbutyl)-4'-triphenylmethyldiphenylamine 0.84N-(4-alpha,alpha-dimethylbenzylphenyl)-2- naphthylamine 0.74 N-(4-alpha,alpha-dimethylbenzylphenyl)- l naphthylamine 0.864,4'-butylidene bis(6-tert.-butyl-metacresol)(Santowhite Powder") 2.24

Example XVII This example demonstrates the usefulness of the compoundsof the invention as processing stabilizers for terpolymers composed ofethylene, propylene, and a small amount of non-conjugated diene.

Two percent by weight of the stabilizer was incorporated intounstabilized rubbery terpolymer, containing for example about 62%ethylene, 33% propylene and 5% dicyclopentadiene, on a mill at F. andthe mixture subjected to milling at 300F. After various milling timesthe Mooney viscosity (ML-4 at 212F.) of the polymer measured. A rise inviscosity is indicative of degenerative cross-linking of the polymer dueto heat and mechanical shearing.

TABLE II Mooney Viscosity vs. Time on 300 F. Mill Example XVIII Thisexample demonstrates the usefulness of the compounds of the invention asstabilizers for synthetic lubricants of the ester type.

To 300 ml. of a synthetic lubricant, namely, di(2-ethylhexyl)sebacate(Plexol 20l.l), is added 5.40 g. (2% by weight) of the antioxidant. Themixture is warmed and agitated to facilitate solution. When ahomogeneous solution is obtained a 15 ml. sample is withdrawn and theneutralization value (ASTM D974 58T) is determined. The Sayboltviscosity is determined on a standard Saybolt viscometer. A 250 ml.sample is placed in a 750 ml. test tube with an open end formed as aground glass joint. A copper washer and iron washer are polished withfine emery cloth, washed with acetone and placed on an air delivery tubehaving a lip to support the washers 6 mm from the lower end of the tubewhich is beveled to allow free air flow. The air tube and washers areinserted in the test tube containing the oil sample to which an Allihntype ground glass joint condenser is connected. The assembly is placedin the well of an aluminum heating block main- (1)Conlrol (unstabilized)I 120 tained at 400F. The flow of cooling water is started (2) '50through the condenser and a source of clean dry air is 3 Z,4,4'-tri5(alpha alpha-dimethyl connected to the air tube and allowed to flowuninterbenzynd'phenylam'ne rupted for 72 hours at a rate of 12.5liters/hour. 5 Example xx I TABLE III Viscosity at 210F.

Saybolt Universal Neutralization Seconds Number Oll loss 811.81

hours 72 hours 0 hours 72 hours 72 hours Sludge 1 4-(1,1,3,3-tetmethy1buty1)-4-trityldipheny1amine n 38 4 -2 17-2 3. Light. (2)z-(alpha-methylheptyl)4,4-bis(alpha,alpha-dimethylbenzyl)dlphenylamme.38 41.0 0 23.3 3.5 Do. (3)z-(alpha-methylheptyl)-4-(alpha,alpha-dimethylbenzyQdrphenylanuno.. 3839.5 0.16 22.6 6.0 Do. (4) N-(4-a1pha, l -dimethlbenzylphenyl)-1-naphthylanune A 38 .4 12- 61 Me ium 4 1 m, i ha-dimothlbenzylphenyl)-2-naphthylamme 38 3 -8 .49 16.2 5.2 Heavy (6)N-(4-a1pha,alpha-dimethylbenzylphenyl)1-alpha,alpha-dlmethylbenzyl)-2-napl1-.

thylamine 38 39. 8 0. 14. O 5. 2 Do, Control 38 43.2 0.25 32.2 5.2 TraceAt the end of 72 hours the oil is allowed to come to room temperatureand the oil loss detemined. The oil sample is filtered, and the Sayboltviscosity, neutralization value (ASTM D 974-58T) and the amount ofsludge are determined.

Example XIX This example demonstrates the usefulness of the compounds ofthe invention as stabilizers for polypropylene in combination withdilauryl thiodipropionate. The stabilizers were incorporated into thepolypropylene (unstabilized Profax 6501) by first milling the resin at340F. for several minutes, then adding the stabilizers to the polymer.The milling was continued for 8-10 minutes. The polymer was then moldedinto plates 90 millimeters thick. Three plates of each sample ofstabilized polymer were aged at 300F. in a circulating air oven. Thebreak point was defined as the first sign of embrittlement or crumblingin two out of the three pieces.

Table V illustrates the synergism obtained with diphenylaminederivatives of the invention with dilauryl 3,3-thiodipropionate both instabilization and color "I ABLE v Days to break at Color at Compound(Cone) 300 F. Initial color break (1) 4,4-bis(1,1,3Metramethylbutyl)diphenylamine (0. 3%) 2 (2) Dilauryl 3,3-thiodipropi0natc (O. 4%) 10 (3) 4,4-bis(1,1,33-tetramethylbutyl)diphenylaminc. (0.1%)} 20 do Dilauryl 3,3 -thi0diropionate 1 (0. 4%) (4) 2,4,4-trls(alpha,alpa-dimethylbenzyl)diphcnylamine (0.1%)} 30 Dilauryl 3,3-thiodipropionatc(O. 4%) (5) 4-(l,1,3,3-tetramethylbuty1)-4-trlty1diphcnylam1ne (0.1%)}48 do Y no 7 a Esta e CB sap HD1138. m6 DHZY 1p euyam YDlluuryi3,8'-thiodlpioplonato .4%)} 62 Off 1 Prior Art.

TABLE IV and indicates their superiority over chemicals of prior Minutesto Compound Resinification (375%) Table V1 18 a further illustration ofthe synergism be- TABLE VI Days to break at Initial Color at Compound(Cone) 300 F. color brcuk (1) D1laury133-thiodi r0 ionate (0- 7) 20Whlte.-... 011 hit (2) 2,4,4-tris(eilpha,al iinlmethylbenzyhdlplieny o.1 71) 41 d w! o Dllauryl3,3-thlo ipropionatc (0.4%) 1 (3) 4,4'-s(alpha,alpha-dlmcthylbenzyl)-2-carboxydiphenylamine (0.1%) 41 Yellow.Yellow. (4 i Pi ii l li t i l 1? l 12 l)-4'i d1 1 1 l (o 1 7) ap aap amey enzy -sopropoxy pieuy am no Dilauryl 3,3-thiodlproplonate 0.4% 31tween the diphenylamine derivatives of the invention and dilauryl3,3'-thiodipropionate.

( l 2-(alpha-methylheptyl)- 4,4'-bis(alpha,alphadimethylbenzyl )di- A9l.l% dispersion of a commercial ASB thermoplastic was made withchloroform as the dispersing agent. The ABS used in all studies containsapproximately 56.5% styrene, 23.5% acrylonitrile, and 20.0% butadieneprepared by the method of Childers and Fisk, U.S. Pat. No. 2,820,773.Atioxidants were dissolved in chloroform and the proper amount added tothe ABS homogeneous dispersion.

Films were prepared on salt plates by evaporation of smears of thedispersions. The films were aged at 400F. in a circulating air oven andthe infrared spectrum examined at specified time intervals. The opticaldensity of the 5.85 y. carbonyl band was plotted against time inminutes. The oxidative life of the polymer containing the anti-oxidantswas defined by a-large increase in the slope of the plot. Table Vlllillustrates the effectiveness of the chemical combinations when comparedto a commercial phenolic system.

TABLE Vlll Oxidative Life- Concentration at 400F. Compound by weight(minutes) Table VII illustrates the effectiveness of thephenylphenylamine I (0.5%) naphthylamine derivatives of the invention asstabiliz- 5 g: (0 5%) ers for polypropylene, their synergism withdilauryl (2)4.(1,1,3,3.temme,hy| 3,3'-thiodipropionate and theirsuperiority over chemlyn- -""y P y amine (0.5%). cals of prior art.

TABLE VII a rea 8 Compound (Conc.) 300 F. Initial color Color at breakN-phenyl l-mpmhylmine $3155.; i la illlfjjjjjjiji gil fi'enow.

( -p y p v n E3; 551;; i gg g g(3)N-(4-a1pha,a1pha-dlmethylbenzylphenyl)-1-naphthy1arnine 23 g (4)N-(4-alpha,alpha-dimethylbenzylphenyl)-2-naphthylamine Light pink B8-(5) N-(4-alpha,a1 ha-dimethyl benzylphenyl)-1-naphthylamine (0.1 7) U"Dilauryl 3,3ghiodipropionate (0.4%)} 32 Whlte Ofi'whlte' (6)N-phenyl-l-naphthylamine (0.1%)} 12 d (7) gna uyl s thprp o iona a 1%,;1

-p enyna t yamine 8) also?seem 1 1, 52%; -a a,ap aime y enzy eny napyamine.

Dilaurgl3,3-thiodlpropionate 0. %Z)} 24 whte 7 Prior Art.

Example XXI dilauryl3, 3-ihiodiro lonate 0.5

This example demonstrates the usefulness of the. gim'ith lmbis-(:t-methylcompounds of the invention in combination with dilau- 30ryl 3,3 '-thiodipropionate as thermal stabilizers for acryzzg g glff l(025% 75 lonitrile-butadiene-styrene thermoplastics. propionate (0.70%)

Having thus described my invention, what I claim and desire to protectby Letters Patent is:

l. A chemical of the formula:

where R, is a phenyl or p-tolyl radical,

R, and R are methyl, phenyl or p-tolyl radicals,

R is a p-tolyl or neopentyl radical,

R is a methyl, phenyl, p-tolyl or Z-phenylisobutyl radical, and

R is a methyl radical.

2. A chemical as in claim 1 which is 4-(l,l,3,3-tetramethylbutyl)-4'-triphenylmethyldiphenylamine.

3. A chemical as in claim 1 which is 4,4- bis(alpha,alpha,p-trimethylbenzyl)-diphenylamine.

i i i i i

2. A chemical as in claim 1 which is4-(1,1,3,3-tetramethylbutyl)-4''-triphenylmethyldiphenylamine.
 3. Achemical as in claim 1 which is 4,4''-bis(alpha,alpha,p-trimethylbenzyl)-diphenylamine.